ITA, La!
LE cant just standby assuming anything when an elderly person goes missing with her personal contents still in her home. It irks me to think they didn't take this seriously at first. I do feel the silver alert wouldn't have helped to save Merrilee but they still should have been one out immediately. She was probably dead before they even knew she was missing since that is what usually happened.

But LE didn't know that.
Don't they do a silver alert for those who have dementia or other mental disabilities? No one knows what happened until the victim is found dead or alive so LE must do all they can immediately to find any missing person. They must always think of all possibilities including she may have been taken from her home against her will. All the signs there showed something wasn't right and they should have picked up on that right away.
They didn't have a silver alert here back when my father was diagnosed with dementia in 1996 and several times he walked off the grounds of the convalescent home. I have to say though the local LE were there within minutes looking for him, along with us, and he was always found in a short period of time thank goodness.
With Merrilee LE had not only a full description of her but her vehicle also so I don't understand why one wasn't sent out immediately once LE discovered she was missing. If they had put out her vehicle description along with her license plate number in a silver alert the very first day, LE may have found her vehicle much sooner along with Merrilee's body as well.
IMO